A blood bank technologist at an academic medical center in Boston reports that his institution uses a protocol of pooling thawed cryoprecipitate that includes adding a small volume of 0.9% sodium chloride to the bag of each thawed product in order to rinse out any residual precipitate into the pooling container. (Their pooling procedure is based on one published in the AABB Technical Manual 14th Edition, page 748; Method 6.12. Thawing and Pooling Cryoprecipitated AHF.)

Recently, however, the institution has have begun to question the necessitiy of using saline (or other diluent) to rinse cryoprecipitate bags during the pooling process. The inquiring colleague has always thought that it was considered 'good practice' to pool cryoprecipitate with a rinse, since he believes it is logical that rinsing would ensure residual fibrinogen, AHF, etc would not be left behind adherent to the walls of product containers. From his personal experience of pooling cryo for the last 25 years, he has found that the volume in a single cryoprecipitate varies greatly, with some containing as little as 5 mL or less, which concerns him. He is interested in learning whether other institutions use a rinse step when pooling cryoprecipitate, and on what data these practices are based.

The following responses have been received.

ADDENDA Aug. 26, 2004

1. A California blood banker reports that her hospital has been using a pooling technique for years where 50 mL of 0.9% saline are added to the first bag of cryo, mixed, expressed to the pooling bag, then the contents of the pooling bag added to the second bag of cryo, then back to the pooling bag, etc. She is of the impression that this approach allows them to extract the maximum amount of cryo from each individual bag, some of which contain only about 5mL.

2. A colleague in Northern California reports that for many years her institution has pooled cryo by adding 10 mL of sterile saline to each bag and then transferring each rinsed bag into a larger pooling bag. In her opinion, this procedure is time consuming and contains multiple opportunities for contamination. However, they continue to use the procedure because the volume of cryo in each bag is so small that most of the product adheres to the original bag if they did not rinse it. She acknowledges that it is interesting and gratifying to know that other institutions also use some method of rinsing cryo bags with saline. She does know one major blood center in Northern California that makes a frozen pooled cryo product.

ADDENDA Aug. 27, 2004

3. A colleague in New Jersey reports that they do not rinse their bags of cryoprecipitate over concerns of contamination. Rather, when pooling the bags, they are rolled using a wooden dowel to force all of the cryo out.

ADDENDA Aug. 31, 2004

4. A colleague in the Pacific Northwest reports that she is aware of two traditional manufacturing 'formats' for single donor cryoprecipitate and a novel prepooled format which is available in her area. One format is to manufacture cryo as a dry button and a second format is to manufacture it as a wet button. "Dry button cryo" contains 5 mL or less and REQUIRES a saline rinse for maximum product yield. "Wet button cryo" contains 15-20 mL and does NOT require a saline rinse. The availability of these two differently formatted cryo units varies by region and by blood product supplier. She suggests that those who wish to avoid pooling cryo in their hospitals might discuss with their blood supplier the possibility of 'prepooled cryo', which consists of a pool of cryo from multiple different donors which is frozen after the pooling is done. The number of units of cryo in such a pool (and therefore the number of donor exposures) is specific to the local manufacturing process. The end user turnaround time for release of this prepooled product for transfusion is as short as 10 minutes.

Editor's query: Are others using a prepooled cryo product, and if so, is this a licensed product that can be shipped across state lines?

ADDENDA Sept. 6, 2004

5. A colleague in Texas reports that 11 years ago when she arrived at her current institution, a saline rinse was being used to help drain each bag of cryoprecipitate into a pool. Much to her distress the saline was obtained from pink clear plastic elliptical-shaped containers with a twist off top, each containing 5 ml. In raised letters were the words: "STERILE-NOT FOR INJECTION 0.9% SODIUM CHLORIDE INHALATION SOLUTION USP”. She immediately discontinued the use of the saline solution, since it seemed fraught with risk of adverse outcomes. She is fearful that other blood banks may be using inappropriate saline solutions for preparation of pooled cryoprecipitate, such as the saline used by respiratory therapists or for blood bank serologic testing.

Editor's note: If a rinse step is used to prepare a pool of cryoprecipitate, it is probably prudent to only use sterile sodium chloride solutions that has been approved for human injection. The saline solution should come in a labeled container that indicates the intended use. See the label examples of an inappropriate and an appropriate solution.

ADDENDA Sept. 7, 2004

6. A colleague adds that if a laboratory is using sterile saline to rinse cryoprecipitate out of its container, one should not forget to document the lot number and expiration date of the saline!!!

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Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator